AntacidsMagnesium HydroxideAluminum HydroxideSimethiconeMagnesium OxideSilicic AcidCalcium CarbonateHeartburnHistamine H2 AntagonistsDrug CombinationsRanitidineSodium BicarbonateCimetidineSiliconesDrug InteractionsEsophagitis, PepticDuodenoscopyBiological AvailabilityFood-Drug InteractionsGastric Acidity DeterminationTechnetium Tc 99m PyrophosphateDosage FormsFamotidineAnti-Ulcer AgentsCarbonatesSucralfateAlginatesDimethylpolysiloxanesEnoxacinGastroesophageal RefluxGastric AcidCross-Over StudiesHydrogen-Ion ConcentrationPneumonia, Aspiration